Re: VFD Selection

George,

Have you considered using a Sherline Spindle? It could be mounted in
place of your router and its speed control would take the place of the
VFD... I use it this way on a couple of my gantry machines...

Hope this helps,

Ballendo

P.S. Using Peter Homann's Digispeed controller with Mach2 you can
have the spindle rpm under gcode control.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "george_barr"
<george_barr@y...> wrote:

> Leslie,
> It appears that I cannot use a VFD or Variac to reduce my router

to

> 1k rpm. What type of motor can I use with a VFD (input: 120VAC,
> output: 120VAC or DC) without getting too expensive or without

using

> servo drives? Is there a specific phase specification. Does the
> motor have to be AC or can it be DC? What I am planning to do is

cut

> mild steel (which requires low rpm speed)?
>
> Thanks,
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Leslie M. Watts"
> <leswatts@a...> wrote:
> > Your Bosch apparently has a phase control already built in
> > as do my Porter Cables. So you don't need another.
> >
> > These speed controllers don't do too well at low RPM due
> > to the lack of a tach or encoder rpm feedback. In any case
> > 1000 rpm would be rough running. Series and compound wound
> > motors just don't have low end torque. That is why the low
> > end is designed to be 8k.There is just not much left below that.
> >
> > A VFD will not work with a universal wound brushed motor.
> > Speed is voltage related in these, which is why Variacs
> > were often used before phase control was cheap.
> >
> > Sounds like you need to drill holes in plastic, etc.
> >
> > I use a modular head where I can quickly bolt on another motor.
> > A PM dc motor makes a pretty good light duty low speed spindle
> > when driven by a dc servo amp, and doesn't cost so much if
> > purchased surplus.
> >
> > A dc servo amp MIGHT work with a router
> > if a tach was added and the phase control bypassed, but it
> > would be a hassle-and although most router motors would work
> > on dc they might not be rated for it. They are definitely
> > not designed for heavy spindle loads either.
> >
> > I work a bit with portable power tool engineering, and we are
> > all looking forward to the day when all of them use brushless
> polyphase
> > induction motors with frequency control. It will happen- but

right

> now
> > commutators are still used due to the cost of brushless drive

power

> > electronics.
> >
> > Les
> >
> >
> > Leslie M.Watts
> > L M Watts Furniture
> > Tiger Georgia USA
> > (706) 212-0242
> > http://www.lmwatts.com
> > Engineering page:
> > http://www.lmwatts.com/shop.html
> > CNC surplus for sale:
> > http://www.lmwatts.com/forsale.html
> > CNC carved signs:
> > http://www.lmwatts.com/signwp.html
> >
> >
> >
> >
> > -----Original Message-----
> > From: george_barr [mailto:george_barr@y...]
> > Sent: Tuesday, April 13, 2004 3:17 PM
> > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > Subject: [CAD_CAM_EDM_DRO] Re: VFD Selection
> >
> >
> > Leslie,
> > It seems to me a Variac only limits the voltage going out. I
> > already tried a variable router speed controller found at:
> > http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?
> itemnumber=43584
> >
> > This router speed controller does not work since my rouers normal
> > speed range is 8k - 20k rpm and I need to have a speed of about 1k
> > rpm. The speed controller cannot slow this router below 8k it
> > seems.
> >
> > Are you saying that a VFD cannot work with my router?
> >
> > Thanks,
> >
> > --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Leslie M. Watts"
> > <leswatts@a...> wrote:
> > > George,
> > >
> > > You don't need a VFD for a unversal wound router motor.
> > > It's speed is not dependent on line frequency.
> > > Typically a phase control triac system is used. It is similar
> > > to a light dimmer but has IR comped backemf or tach feedback
> > > to contol the speed.
> > >
> > > Granger, MSC, etc have many of these, and some are well under
> > > $100.
> > >
> > > A variac works as well, but with poorer speed control.
> > >
> > >
> > > Leslie M.Watts
> > > L M Watts Furniture
> > > Tiger Georgia USA
> > > (706) 212-0242
> > > http://www.lmwatts.com
> > > Engineering page:
> > > http://www.lmwatts.com/shop.html
> > > CNC surplus for sale:
> > > http://www.lmwatts.com/forsale.html
> > > CNC carved signs:
> > > http://www.lmwatts.com/signwp.html
> > >
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: george_barr [mailto:george_barr@y...]
> > > Sent: Tuesday, April 13, 2004 2:34 PM
> > > To: CAD_CAM_EDM_DRO@yahoogroups.com
> > > Subject: [CAD_CAM_EDM_DRO] VFD Selection
> > >
> > >
> > > I want to get a VFD for my Hitachi M12V router so I can vary the
> > > speed for metal, aluminum, and wood milling. The M12V is a
> single-
> > > phase series commutator motor, 115VAC, 60HZ, 15 Amps router. I
> > would
> > > like to use my 120VAC outlet for the VFD. Can someone tell me
> what
> > > kind of VFD I should get? I have noticed some VFD have 3 to 1
> phase
> > > conversion and all sort of specifications. I certainly do not
> want
> > > to buy the wrong one. Also, it should interface to my pmdx.com
> > break
> > > out board.
> > >
> > > Thanks,
> > >
> > >
> > >
> > > Addresses:
> > > FAQ: http://www.ktmarketing.com/faq.html
> > > FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> > > Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
> > >
> > > Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> > > Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> > > List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com,
> wanliker@a...,
> > > timg@k...
> > > Moderator: pentam@c... indigo_red@q... davemucha@j...
> > > [Moderators]
> > > URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> > >
> > > OFF Topic POSTS: General Machining
> > > If you wish to post on unlimited OT subjects goto:
> > > aol://5863:126/rec.crafts.metalworking or go thru Google.com to
> > reach it if
> > > you have trouble.
> > > http://www.metalworking.com/news_servers.html
> > >
> > > http://groups.yahoo.com/group/jobshophomeshop I consider this

to

> > be a
> > > sister site to the CCED group, as many of the same members are
> > there, for OT
> > > subjects, that are not allowed on the CCED list.
> > >
> > > NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY

POSTING

> > THEM.
> > > DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> > > bill
> > > List Mom
> > > List Owner
> > >
> > >
> > > Yahoo! Groups Links
> >
> >
> >
> > Addresses:
> > FAQ: http://www.ktmarketing.com/faq.html
> > FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> > Post Messages: CAD_CAM_EDM_DRO@yahoogroups.com
> >
> > Subscribe: CAD_CAM_EDM_DRO-subscribe@yahoogroups.com
> > Unsubscribe: CAD_CAM_EDM_DRO-unsubscribe@yahoogroups.com
> > List owner: CAD_CAM_EDM_DRO-owner@yahoogroups.com,

wanliker@a...,

> > timg@k...
> > Moderator: pentam@c... indigo_red@q... davemucha@j...
> > [Moderators]
> > URL to this group: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO
> >
> > OFF Topic POSTS: General Machining
> > If you wish to post on unlimited OT subjects goto:
> > aol://5863:126/rec.crafts.metalworking or go thru Google.com to
> reach it if
> > you have trouble.
> > http://www.metalworking.com/news_servers.html
> >
> > http://groups.yahoo.com/group/jobshophomeshop I consider this

to

> be a
> > sister site to the CCED group, as many of the same members are
> there, for OT
> > subjects, that are not allowed on the CCED list.
> >
> > NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY

POSTING

> THEM.
> > DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
> > bill
> > List Mom
> > List Owner
> >
> >
> > Yahoo! Groups Links